Senegal: An attack by suspected extremist militants on motorbikes killed at least 25 soldiers Thursday in the West African nation of Niger, adding to a death toll that has surged in recent weeks as troops struggle to contain violent extremism in the region.

At least 25 soldiers have been killed in an attack on a military camp along the western border with Mali, Niger’s army says.

More than 60 militants were also killed when the army – supported by partners – responded with air power, it says.

According to the details, The attack coincides with a campaign by Islamist groups connected to al Qaeda and the Islamic State group to force the Nigerien army back from its western frontier with Mali where government control of the rural centre and north has all but evaporated because of the rise of jihadists.

Despite efforts by international forces to stop them, attacks have risen fourfold this year in Niger, killing nearly 400 people, according to data from the Armed Conflict Location & Event Data Project, a non-profit research organization.

Groups allied to both the Islamic State group and al-Qaeda are active in Niger.

65 killed in Nigeria Boko Haram attack

Earlier, Two helicopters full of French troops pursuing militants in a remote region of Mali collided, killed 13 soldiers.

This was the heaviest single loss for the French military in nearly four decades, police officials said.

The accident occurred late Monday when three helicopters and a squadron of Mirage jets arrived to support ground troops pursuing extremists in the Liptako region, near the borders of Burkina Faso and Niger, the defence ministry said.

The accident brought to 41 the number of French troops killed in the Sahel region since Paris intervened against al-Qaeda-affiliated fighters in Mali in 2013.